function checkForValidUrl(tabId, changeInfo, tab) {
    if (tab.url.indexOf('mbl.is/') > -1) {
    chrome.pageAction.show(tabId);
  }
};

function onButtonPressed(tab) {
  chrome.tabs.executeScript(null,
			    { file: 'makeBigger.js' });
}

chrome.tabs.onUpdated.addListener(checkForValidUrl);


chrome.pageAction.onClicked.addListener(onButtonPressed);
